Prior gas traps contain bubble tubes which extended into reactants which removed selected pollutants from gas cycled through these devices. Fritted ends have also been employed on the bottom of such bubble tubes. Purification was accomplished by the reactant trapping the pollutants in amounts related to reactant concentration and in proportion to the time the gas to be treated was exposed to the reactant.
These prior structures varied in efficiency and disadvantages remained with all. One common disadvantage was that too little of the reactant in the enclosure was actually exposed to the polluted gas as the gas bubbled to the surface. A related common disadvantage was that the gas passed quickly through the reactant fluid, thereby not giving the cleansing reaction time to occur with respect to much of the pollutant. Due to these disadvantages, for a given reactant, the desired purification reaction would either be only partially completed or not occur at all for many of the polluted gas bubbles. Additionally, these disadvantages in turn limited the gas flow rates which could be utilized with the prior gas traps. Dramatic drops in efficiency commonly occurred for prior gas traps when flow rates exceeded 25 milliliters per minute.
The present invention alleviates the disadvantages indicated above by delaying the polluted gas within the reactant during its rise by causing the reactant and the bubbles to roll for a brief time at the base of the restricted passageway. The shape of the enclosure and the position of the restricted passageway relative to the lower chamber, alone accomplish this improved result. Complications such as valves and mutliple compartments within the trap are avoided. Further, by an appropriate choice of cross-sectional dimensions for the restricted passageway, for certain pollutants and reactants, flow rates as high as 300 milliliters per minute can be utilized while retaining a high degree of efficiency.